What's your blog about? I blog about how energy works, sustainability and renewable resources, political issues around change with energy policy, new technology, systems change, altruism and environmental action.

How long have you been blogging? Oakleigh blog was launched in December 2008.

What's your favorite part of blogging? Blogging connects me to other people of like minds and helps us be more creative about solving insurmountable problems and finding a balance in our lives.

List three or four of your favorite or most popular posts.

Saving Energy Dollars in Your Home, Lessons in Self-Reliance, and my vblog Vermont Waterfall are my favorite posts to date. But the creativity and energy I fell tells me my posts are continually improving and they get better and better!

What You Need to Know About Mercury

Mercury was one of the first metals known and its compounds have been used throughout history since at least 1500 BC. And the first account of mercury poisoning was recorded as early as 50 B.C. Mercury nitrate was used to preserve 19th century beaver felt hats and hat makers would go mad as a result of breathing the toxic mercury fumes.

During the past 50 years a growing body of scientific evidence has suggested that mercury emissions from human activities are having widespread impacts on environmental and human health.

(Environmental Protection Agency)Nowadays we know that mercury is a neurotoxin and that high levels of exposure can lead to severe birth defects, serious illness and, in extreme cases, death.

Image courtesy of bionerd at Flickr

Since 1800, mercury in the environment has increased 400%, largely because of human activities. Mercury has always been emitted from natural sources such as volcanic eruptions, the weathering of soils and rocks and vaporization from the oceans; however, scientists believe that more than half of the mercury in the environment today is from human sources, estimated globally at approximately 2,000 tons each year.

Today, there are still many commercial and industrial applications in which mercury is used including thermometers, dental fillings and fluorescent light bulbs, and it is released from a range of industrial processes such as the generation of electricity from burning fossil fuels, and waste incineration. For these reasons mercury ends up in the atmosphere as particle air pollution, as runoff from mining waste, eventually flowing into rivers and lakes and ending up in food chains.

Mercury can combine with other chemicals to form 'methylmercury' that dissolves and stays in fish as part of their tissue. Fish accumulate the mercury, making fish unsafe to eat, especially by pregnant women. Mercury is very dangerous to the fetus and can cause severe birth defects, as well as some effects in adults of which are irreversible. Irritability is one of the early symptoms of mercury poisoning and later, nerve damage, blindness and death can result.

Methylmercury is much more toxic than the original metal molecules that drifted into the air, and has the ability to migrate through cell membranes and "bioaccumulate" in living tissue. Bioaccumulation is the process by which a substance builds up in a living organism from the surrounding air or water, or through the consumption of contaminated food.

The bioaccumulation of methylmercury in natural ecosystems is an environmental concern because it inflicts increasing levels of harm on species higher up the food chain. This occurs through a process known as "biomagnification", whereby persistent substances like methylmercury will increase in concentration from microorganisms, to fish, to fish eating predators like otters and loons, and to humans. Elevated methylmercury levels may lead to the decline of affected wildlife populations and may affect human health when people consume significant quantities of fish or other contaminated foods. For more information on mecury in the environment see National Wildlife Federation

Although states have passed laws banning mercury thermometers in schools and limiting fuels and waste with mercury, the highest human exposure to mercury is typically in your mouth. Mercury amalgam fillings continually evaporate mercury gas into your mouth, which can be inhaled into your lungs and bloodstream. Unfortunately removing the fillings can result in the release of larger amounts of mercury so most health experts suggest leaving mercury fillings alone.